The goal of this study is to determine the effects of a shortterm infant-centered intervention (Neonatal Behavioral Assessment Scale-NBAS) on the behavior and development of mothers and children at risk for parent-child interactive disturbances. The at- risk population is intrauterine growth retarded (IUGR) infants of lower SES and their mothers. Non-IUGR infants are included to provide contrast for tests of long term consequences of IUGR as well as of the intervention. Inclusion of upper and middle as well as lower SES subjects enables us to test for the effects of SES, including the interactions of SES, intervention, and IUGR on later outcome. 65 IUGR and 68 non-IUGR full-term clinically normal infants have been randomly assigned to experimental and control treatment conditions. The experimental intervention consists of 3 demonstrations of the infant's behavior to the mother using the NBAS on days 3, 14, and 30 postbirth. In the control group (which is not a non-treatment group but is actually a second type of intervention) the NBAS assessments are also done on days 3, 14, and 30 but the mothers are not present and instead participate in a mother-centered interview focusing on medical , behavioral, and caregiving issues. At 4, 12, and 24 mos. the mother and child are followed in the laboratory. Dependent variables include maternal and emotional wellbeing, maternal behavior towards the child in interactive situations, child mental and motor development, attachment, child growth and health history, and child social behavior and affect. Included among outcome assessments of these variables are the Bayley, the face-to-face paradigm, the Ainsworth Strange Situation, teaching and frustration tasks, psychosocial interviews, medical exams, and stress and temperament questionnaires. At 8 mos. an additional contact via home visit is made to determine what information the mothers remember from the initial 3 sessions and how useful this information is in caregiving. Analysis of variance, regression, and analysis of covariance structures will be used to assess the effects of birth size, intervention, and the transactional model of development. Initial analyses indicate that our IUGR sample was significantly smaller and that birth size was associated with mothers' reported smoking. IUGR infants had significantly poorer performance on the NBAS on day 3. Over the first month of life, NBAS scores for NBAS intervention were significantly better than control subjects.